Continuous feeding and decompressing device, tube assembly, and methods

ABSTRACT

A decompressing and feeding device for safely feeding in the gastrointestinal tract of a recovering patient continuously aspirates and feeds at a rate commensurate with the ability of the intestines to absorb fluids including nutrient. Air is also aspirated in the process so that neither air nor excess fluids cause distension in the gastrointestinal tract. Digestive juices and nutrients that are aspirated are continuously refed together with unused feeding material into the gastrointestinal tract at a location that more efficiently moves and digests the food. The device may include two aspirate reservoirs to and from which aspirate is alternatingly transferred. To provide the continuous and alternating flow, a solenoid valve and timer switch device is provided. Alternatively, a device with a single aspirate reservoir to which and from which aspirate is transferred can be used. A feeding and aspirating tube assembly having a plurality of separable lumens can be incorporated.

This application is a continuation-in-part of patent application Ser.No. 10/419,036, filed Apr. 18, 2003, and entitled “CONTINUOUS FEEDINGAND DECOMPRESSING DEVICE AND METHOD”, the disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention generally relates to a device used to aspirate agastro-intestinal tract and/or to deliver nutrients, fluids, medication,and/or aspirate into the gastro-intestinal tract. The inventionspecifically relates to devices including feeding tubes, and methods forsafely, efficiently, and/or continuously aspirating from and feedinginto the gastro-intestinal tract.

2. Background Art

Frequently, hospital patients are unable to consume food normally. Inthese situations, it is often necessary to use a feeding tube to providenutrition, fluids, and/or medicine. Such a tube is inserted into apatient's gastro-intestinal tract through the nose (nasogastric ornasoenteric tubes) or surgically by means of a gastrostomy orjejunostomy. Because adequate nutritional intake facilitates recovery,the proper use of a feeding tube and an associated device for feedingthrough the feeding tube can greatly benefit a patient.

However, the feeding tubes and the associated devices and methods alsopose some discomfort, and even some potential risks, to patients. Anumber of commercially available feeding tubes exist. Unfortunately, allpresently available feeding tube devices and methods for feeding throughthe tubes suffer from a variety of deficiencies. One common problem isthat a feeding tube may deliver the fluids (which include liquidnutrition, hydrating fluids, and medicine to the patient) at a rateexceeding the ability of the gastro-intestinal tract to absorb suchfluids. This results in an accumulation of fluid within the intestine.In particularly bad cases, accumulation of fluid causes distension ofthe intestine that leads to the temporary loss of all residualintestinal function. In rare cases, this intestinal distention mayinduce fatal vagal reflex circulatory changes. Approximately 1 in 1000patients that are fed through ajejunal tube die of bowel necrosis, acomplication that may be related to the lack of safety of the devicesand methods of feeding directly into the gastro-intestinal tract.Severely ill, malnourished patients are most at risk for developingcomplications associated with overfeeding. Aside from being at highrisk, these patients are also most in need of the earliest optimumnutrition. In any case, when a patient's intestine is not operatingfully, then the amount of nutrition the patient can receive is limited.However, adequate nutrition is obviously a critical part of anyone'shealth and is necessary in order to provide optimum recovery for apatient. It is thus desirable to deliver as much nutrition to a patientas can be absorbed safely by the patient's impaired gastro-intestinaltract. Devices and methods of the past are deficient in providing thismaximum feeding in a safe, prompt, and effective way to patients inneed.

It is not desirable to simply deliver a maximum amount of nutrition intoa patient's intestine. The reason for this is that overfeeding, which isdelivering feedings at a rate exceeding the ability of the patient'sgastro-intestinal tract to absorb its own secretions plus the addednutrition, itself presents serious hazards to a patient. Overfeeding apatient leads to an accumulation of fluid, which distends the intestine.This intestinal distension can lead to fatal circulatory changes, as setforth above. More commonly, complications from overfeeding include thetemporary further impairment of intestinal function, with nausea andvomiting, which at a minimum causes discomfort and delays recovery. Acommon and more severe related complication is impaired ability tobreathe deeply and cough because of abdominal distention, resulting inatelectasis and pneumonia.

A patient's impaired digestive system may also produce too manydigestive secretions for the patient to reabsorb immediately. A typicalperson secretes seven to eight liters of fluid per day, starting withsaliva. All secretions normally are reabsorbed by the intestine, withoutnet loss or gain of fluid for the body. Unfortunately, during recoveryfrom surgery the level of secretions remains relatively constant ordecreases, while the intestine's ability to absorb secretions istypically impaired, sometimes severely. The result can be a build up offluid in the intestine, with the same detrimental side effects as foundwith over-feeding. The problem of digestive secretions can beexacerbated by feeding.

When concentrated nutrition is delivered to a patient'sgastro-intestinal tract, the body's natural response is to producedigestive secretions to dilute the feedings and break down the complexnutrients for absorption by the intestine. However, if a patient'sgastro-intestinal function is severely impaired only a portion of thetotal fluid may be absorbed. By way of example, for 2 ml of nutritiondelivered to the gastro-intestinal tract, 10 ml of digestive secretionsmay be provided in response. The intestine may temporarily be capable ofabsorbing only 2 ml of fluid, resulting in a net increase of 10 ml tothe volume of fluid in the gastro-intestinal tract. Thus, nutritiondelivered to the intestine may be competing with digestive secretionsfor absorption by the intestine. This problem may worsen as feedingscontinue, causing progressive intestinal distension which, in turn,further impairs intestinal function and reduces the amount of nutrientactually being absorbed. To avoid problems of overfeeding or excessivesecretion build up during recovery, a patient's gastrointestinal tractmay be aspirated to remove excessive fluid. However, any secretionsremoved in this way will cause a net loss of fluids and dehydration ofthe patient. Past solutions to this problem include providingreplacement fluids in the form of an intravenous saline solution.However, this method of fluid replacement does not conserve nutrientsand digestive juices that may have otherwise been used.

Another problem that has not adequately been solved is that the verypresence of a nasal feeding tube stimulates swallowing by the patient,introducing additional air into the intestine. The presence of airwithin the gastro-intestinal tract interferes with the propulsion andabsorption of nutrition and can be quite uncomfortable or painful to apatient. The use of an aspirating tube to remove air from thegastro-intestinal tract has been used to combat this problem. As setforth above, aspirating introduces additional problems of increasedrisks of dehydration and removal of potentially beneficial nutrients.

Unfortunately, the use of a second tube for aspiration presents newproblems. The introduction of a second tube only adds to the pain anddiscomfort experienced by a patient. Furthermore, if a separate secondtube is used, it may be difficult to effectively locate it proximate tothe feeding tube, thereby preventing it from aspirating excessive foodpresent in the gastro-intestinal tract.

In conjunction with systems of the past that have been used for feedingand aspirating, tubes with more than one lumen integrated in a singletube have been used. These tubes are typically manufactured with aplurality of lumens that are permanently formed as part of the tubes.Thus, the feeding tubes of the past are deficient enabling assembly anddisassembly after the time of manufacture. Furthermore, themanufacturing process required in order to make feeding and aspiratingtubes having a plurality of permanent lumens is relatively expensive andintricate.

DISCLOSURE OF THE INVENTION

The present invention overcomes the many deficiencies of the past andhas many advantages as will become apparent in the following disclosureand description. Accordingly, the invention relates to a device forproviding as much nutrient to the gastro-intestinal tract as possiblewithout overfeeding, for example, in a patient recovering from surgery.The invention also includes a device and a method that improves theefficiency of absorption in the gastro-intestinal tract by removing gasand by stepping a feeding material forward to a location in whichgreater peristaltic activity promotes greater absorption and flow. Thedevice and method further reduce the tendency to dehydration of pastdevices and methods. The present invention incorporates the principlesof the Applicant's prior inventions disclosed in U.S. Pat. No.6,447,472, filed Oct. 19, 2000, and issued Sep. 10, 2002, the disclosureof which is incorporated herein by reference. The present invention hasmany added features, structural differences, and utilizes distinctmethods. The new aspects safely provide continuous aspiration andcontinuous feeding and other advantages that have not been adequatelyaddressed by devices and methods of the past.

It is to be explicitly understood that the devices and methods of thepresent invention are not limited to use in human patients, but may beused in veterinarian applications or even in other non-medicalapplications. Furthermore, it is to be understood that while the devicesare specifically applicable in the gastro-intestinal tract of a body,the devices may also be useful in other organs or systems of the human.Therefore, the disclosure directed specifically to the application ofthe devices and methods for feeding and decompressing in thegastro-intestinal tract is to be considered exemplary and notrestrictive. The limitations of the devices and methods are to beinterpreted in accordance with the appended claims.

In one aspect, the invention comprises a feeding and decompressiondevice for feeding into and aspirating from an intestinal tract. In thisaspect, the device includes a first aspirate reservoir and a secondaspirate reservoir each connected to an aspiration channel. A vacuumsource is alternatingly fluidly connected to the first and the secondaspirate reservoirs and induces a flow of an aspirate from theaspiration channel to at least one of the reservoirs at a time.

To facilitate the switching between the reservoirs, the device includesa solenoid valve connected to the first and second aspirate reservoirsand to the vacuum source. A timer switch connects a power source to thesolenoid valve so that the timer switch and solenoid valve alternatinglyfluidly connect the first and second aspirate reservoirs with the vacuumsource. Furthermore, the timer switch and the solenoid valve connect thereservoir that is not connected to the vacuum source to a vent.Specifically, the first and second reservoirs can be continuouslyswitched back and forth between being connected to the vacuum source andthe vent so that one reservoir is always connected to the vacuum sourceand one is always connected to the vent.

In another aspect of the invention, the device simply comprises asolenoid valve and timer device for alternating valves of the devicebetween positions. In this aspect, the device includes a solenoid and avalve housing having at least four connection points for connecting aplurality of fluid lines. The valve housing is connected to the solenoidsuch that the solenoid operatively controls at least two valves withinthe housing. The solenoid and timer device has an adjustable timer thatmeters time for a cycle of a predetermined period of the time. Theadjustable timer is connected to the solenoid and to a switch so thatthe switch alternates between an open and a closed state forpredetermined portions of the cycle. This cycle can be repeatedindefinitely. A source of power is connected to the solenoid by acircuit that includes the switch. Thus, the switch is alternatinglyclosed and opened by the timer, whereby power from the power source iscorrespondingly applied to and removed from the solenoid. The powerbeing repeatedly turned on and off causes the solenoid to simultaneouslymove the at least two valves between a first position and a secondposition.

In this aspect, the power can actuate any number of valves by any numberof members. However, the at least two valves can be provided by a singlemotive member. The single motive member can provide a rotary valve.Alternatively, the motive member can include a piston member.

The timer can be provided as a mechanical or electromechanical timer.The timer can be provided by a microcircuit. In this regard, it iscontemplated that at least a portion of the switch can also be providedby the microcircuit.

In still another aspect, the invention has a feeding and decompressiondevice providing substantially constant aspiration during feeding yetdoes not require a solenoid valve and a timer. In this aspect, theinvention incorporates a single aspirate reservoir and provides constantaspiration and feeding by a means other than switching between two ormore such reservoirs. In this aspect, a feeding and decompression deviceincludes at least one aspirate reservoir having an aspiration port and afeeding port. An aspiration channel is connected to the aspiratereservoir via the aspiration port. A feeding channel is connected to theaspirate reservoir via the feeding port. A vacuum source is connected tothe aspiration channel for drawing aspirate toward the aspiratereservoir. The vacuum source in this aspect of the invention can beprovided by an electric pump fluidly connected directly to theaspiration channel.

The invention includes a method of feeding and decompressing. Inparticular, the invention includes a method of feeding and decompressingin a gastro-intestinal tract. The method includes initial steps ofplacing a distal end of a feeding channel at a first position and adistal end of an aspiration channel at a second position that is spacedproximally relative to the first position. In accordance with themethod, digestive juices and any nutrient or feeding material thereinare continuously aspirated via the aspiration channel. In accordancewith one aspect of the method, the step of continuously aspiratingfurther comprises substantially collapsing a portion of the jejunum atthe second position. The method further comprises continuously feedingvia the feeding channel.

In one aspect of the method, the steps of continuously aspirating andcontinuously feeding further include aspirating into at least one of aplurality of aspirate reservoirs at a time through the aspirationchannel. In accordance with the method, the aspiration channel can becommon to all of the aspirate reservoirs.

In another aspect of the method, the step of continuously feedingincludes feeding from one of the plurality of aspirate reservoirs intowhich nothing is being aspirated. That is, aspirate can be directed intoother(s) of the plurality of aspirate reservoirs simultaneously with thestep of feeding from the one aspirate reservoir into the feedingchannel. The method further includes supplying the feeding channel withfeeding material from an unused feeding material line and from at leastone refeeding line connected to another of the aspirate reservoirs.

In still another aspect of the method, the step of continuously feedingfurther comprises returning at least a portion of digestive juices andfeeding material to the first position that were previously aspirated atthe second position. This return of digestive juices reduces thetendency of dehydration in a patient. The return of the feeding materialreduces waste of the material. However, this refeeding and feeding mustbe accomplished in a way that avoids physiological harm and discomfort.Therefore, the method of feeding and decompressing further includesinhibiting distending of the gastro-intestinal tract. This is achievedby limiting an amount of aspirate that is fed and refed into the feedingchannel during a certain period of time. As such, the method not onlyincludes simultaneously impeding overfeeding, distending, anddehydration, but also facilitates obtaining direct feedback regardingabsorption of a feeding material in the gastro-intestinal tract. Thisfeedback can be in the form of observing a volume of aspirate that isgreater than a predetermined amount. Thus, the method can also includeadjusting the pressure or the flow resistance in the feeding channel sothat a volume of aspirated fluid during a period of time issubstantially equal to or less than the volume absorbed during the sameperiod of time.

Other advantageous aspects of the method are improving an efficiency ofdigestion and absorption by removing gases from a gastro-intestinaltract and by stepping a feeding material forward in thegastro-intestinal tract to a location where greater peristaltic activityfacilitates absorption. As can be appreciated, the efficiency can beimproved to a case specific and time dependent maximum by the steps ofobserving and adjusting as set forth above. To this end, the volume ofaspirate returned plus the unused feeding material to be fed can be madeto be substantially equal to the volume absorbed. As long as the sum ofthe fluid to be fed is not greater than the fluid being absorbed,overfeeding will be avoided.

The combination feeding and decompression or aspiration tube can beformed as a feeding tube assembly that overcomes deficiencies of pastdevices and provides a readily assembleable unit that can be puttogether by a doctor or an assistant in a hospital. Thus, the expensiveplural-lumen feeding and aspirating tubes of the past can be replaced bya simple combination of an inner and an outer tube assembled together toform the feeding tube of the present invention. In particular, thisfeeding tube can be ajejunal feeding and aspirating tube for the severalreasons and specifics set forth herein.

In a simple form, the feeding and aspirating tube assembly includes afirst outer aspirating tube and a second inner feeding tube. The secondinner feeding tube is removably disposed inside the first outeraspirating tube. The outer tube has a branch portion having at least twobranches. One of the branches can be selectively used to guide an innertube through an external opening and into an interior of the outer tube.The other of the branches can be connected to a vacuum or pump sourcefor aspirating therethrough from within the outer tube.

Many of the aspects of the present invention provide the advantage ofenabling feeding of a fine feeding material and closely monitoring apatient and the amount of feeding material being absorbed in the earlystages after an operation. Subsequent to this feeding and monitoringperiod, when a patient's gastro-intestinal tract is capable ofconsistently absorbing more feeding material, the fine feeding materialcan be replaced by a coarser feeding material and the combinationfeeding and aspirating tube can be replaced by a subset of the feedingand aspirating tube combination. That is, the feeding tube can bewithdrawn from within the outer aspirating tube and the aspirating tubecan be used for both feeding courser feeding material and foraspirating. Alternatively, a separate feeding tube can be used to feedthe courser material.

The foregoing and other features and advantages of the present inventionwill be apparent from the following more detailed description of theparticular embodiments of the invention, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a system including a device accordingto a first embodiment of the present invention, depicting a use forfeeding and decompressing in a gastro-intestinal region of a patient;

FIG. 2 is an enlarged diagrammatic view of the device of the embodimentshown in FIG. 1;

FIG. 3 is a schematic representation of the solenoid valve and switchdevice that is included in the device of FIGS. 1 and 2; and

FIG. 4 is a diagrammatic view of a device according to a secondembodiment of the invention.

FIG. 5 is a diagrammatic view of the system of FIGS. 1–2 andincorporating a particular feeding tube assembly in accordance with oneaspect of the invention;

FIG. 6 is an exploded perspective view of the feeding tube assembly ofFIG. 5; and

FIG. 7 is sectional view of an encircled portion indicated at 7 in FIG.5.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As discussed above, embodiments of the present invention relate todevices and methods for feeding and decompressing in a gastro-intestinaltract. As shown in FIG. 1, an aspirate storing and refeeding device 10is used to feed and decompress in a gastro-intestinal tract 15 of apatient 20. To this end, a combination feeding and aspirating tube 25 isinserted into the gastro-intestinal tract 15 through the nose andesophagus. Other ways of accessing the gastro-intestinal tract includeinserting the tube through the abdominal wall directly into the jejunum,or directly into the stomach and intraluminally to the jejunum. As canbe appreciated from FIG. 1, the combination feeding and aspirating tube25 is a double lumen tube and comprises an aspiration channel 30 and afeeding channel 35 for handling flow in opposite respective directions.Combining these channels 30, 35 into a single composite tube 25 has theadvantage of reducing bulk and complexity in the inserted portion of thechannels 30, 35. The aspiration channel 30 has a distal end 40 includingan opening 45 for aspirating fluids including digestive juices andfeeding material. Additional openings located at spaced intervalsproximally from the distal end 40 along the aspiration channel 30 may beprovided. This has the effect of aspirating along a greater length ofthe gastrointestinal tract as indicated by the collapsed region shown inFIG. 1. The feeding channel 35 has a distal end 50 extending distallybeyond the distal end 40 of the aspiration channel 30. The distal end ofthe feeding channel 35 has an opening 55 for delivering feeding materialand other fluids as will be described below. Preferably, the distal end50 and the opening 55 of the feeding channel 35 is spaced distally fromthe distal end 40 and opening 45 of the aspiration channel 30 byapproximately ½ inch. Depending on the particulars of the cite at whichthe channels are placed, the separation of the most distal openings 45,55 may be in the range from ¼ inch to 12 inches. In most cases, theseparation of the distal openings 45, 55 of the aspirating and feedingchannels 30, 35 will not exceed approximately 6 inches.

In one embodiment, the device 10 comprises a first aspirate reservoir 60and a second aspirate reservoir 65. The reservoirs 60, 65 can beprovided in the form of burettes having single lumen combination feedingand aspirating lines 70, 75 for handling both aspiration and refeedingof aspirate to and from the reservoirs 60, 65, respectively. Thecombination feeding and aspirating lines 70, 75 generally handle flow inonly one direction at a time, either toward or away from the reservoirs60, 65. However, flow in one of the combination feeding lines isgenerally in an opposite direction relative to flow in the other of thecombination feeding and aspirating lines 70, 75. Thus, there is analternating pattern of aspirating into the first reservoir 60 for afirst half of a cycle and then aspirating into the second reservoir 65for a second half of the cycle. Meanwhile, the second reservoir 65refeeds aspirate for the first half of the cycle and the first reservoir60 refeeds aspirate for the second half of the cycle. This alternatingpattern can be repeated indefinitely during feeding. It is to beunderstood that refeeding need not be continuous during all of the halfcycles. Likewise, aspiration flow may cease at any point during each ofthe half cycles. Additionally, the cycles need not be divided intohalves. Rather any alternating pattern of time is considered to bewithin the scope of the invention.

In order to effectuate the alternating pattern of aspirating andrefeeding, the device includes a system of lines 80, 85, 90, 95, one-wayvalves 100, and a solenoid valve 105 for alternatingly connecting thereservoirs to a vacuum source 107. The one-way valves 100 permit flow inthe lines 80, 85, 90, and 95 only in the directions indicated by thearrows in FIG. 2. Thus, when the solenoid valve 105 connects either ofthe reservoirs 60, 65 with the vacuum source 107, only flow through theaspirating lines 80 and 90 is induced, which in turn induces flow fromthe aspiration channel 30. When the vacuum source 107 is disconnectedfrom one of the reservoirs 60, 65, the contents of that reservoir arepermitted to flow out through one of the feeding lines 85, 95,preferably under the influence of gravity. Alternatively, a pump orvacuum source 107 could be connected to the feeding channel 35 to drawand refeed the aspirate into the feeding channel 35. A filter 108 canalso be placed in the aspiration channel 30 or between the aspirationchannel 30 and the aspirating lines 80, 90 as shown in FIG. 2.

As shown, the device 10 is in addition to the feeding system that istypically used in hospitals. As such, a feeding material is provided ina feeding bag 110. The feeding bag is connected to the feeding channelby an unused feeding material line 115. The flow of the feeding materialinto the feeding channel 35 is affected by the capacity of the feedingchannel 35, the pressure at which the feeding material is fed from thefeeding bag 110, (such as by a pump), and the flow rate of the aspiratethat is being refed into the feeding channel 35. These and other factorscan be adjusted to adjust the flow of feeding material into the feedingchannel. Preferably, the flow from the feeding bag 110 can be reduced inproportion to a flow of aspirate that is refed. Thus, waste of unusedfeeding material is avoided. Furthermore, nutrients and digestive juicesthat typically have been discarded in the past can be reintroduced andabsorbed with little or no loss of fluids and nutrients.

The device 10 also enables the aspiration to be applied continuously.That is, vacuum from the vacuum source can be applied substantiallyconstantly. Flow of the aspirate may not be constant or continuous dueto a presence or a lack of presence of fluids in the portion of thegastrointestinal tract being aspirated. However, continuous and/orconstant aspiration has the advantage of continuously removing gasesfrom the gastrointestinal tract as there is no interval without suctionduring which gas may be propelled by peristalsis distal to the mostdistal aspiration orifice. Removing these gases has the advantages setforth above. Furthermore, removing the gases continuously or constantlyhas the advantage of preventing distending of the intestines due tobuild up of these gases.

Ideally, when the length of the half cycles are set properly, bothrefeeding flow and aspiration flow can be continuous, if not constant.With more constant and/or continuous flow in the feeding channel, thefluctuation of flow into the gastrointestinal tract is reduced. Byproviding less fluctuation in the flow into the intestines, distendingcan further be prevented. Furthermore, nutrients and fluids will be moreconstantly available for absorption by the intestines.

A predetermined volume of aspirate to be retained in the reservoirs 60,65 can be selected and set. This volume also affects the “head” orpressure due to gravitational forces that causes the flow of aspirateout of the reservoirs 60, 65. Preferably, a maximum predetermined volumeto be retained in each reservoir 60, 65 during each half cycle is in therange from 10 to 15 cc. This reduces the chance for overfeeding, forexample when the half cycle is kept to approximately ½ minute. Perhaps amaximum adjustable volume could be as much as 35 cc. Adjustment of thepredetermined volume is achieved by adjusting the depth 120 of a lowerend 125 of a first draw tube 130 in the first aspirate reservoir 60.Similarly, the maximum volume of aspirate to be retained in the secondaspirate reservoir 65 can be adjusted by adjusting a depth 120 of alower end 135 of a similar second draw tube 140.

The draw tubes 130, 140 connect the aspirate reservoirs 60, 65 to firstand second overflow chambers 145, 150. These tubes also provide fluidcommunication between an interior of each of the reservoirs 60, 65 andthe solenoid valve 105. Thus, draw tubes 130, 140 connect the aspiratereservoirs to the vacuum source 107 in an alternating pattern as will bedescribed in further detail below. The draw tubes 130, 140 act to removeaspirate in excess of the predetermined maximum volume and draw theexcess aspirate into respective overflow chambers 145, 150. The overflowchambers 145, 150 may have any reasonable volume. Preferably, the volumeof each overflow chamber is in the range from 200–4000 cc, with 1000 ccbeing a fairly standard capacity. Once removed, the excess aspirate canbe discarded or refed later when the flow of aspirate from theaspiration channel 30 has decreased.

The first and second overflow chambers 145, 150 are connected to thesolenoid valve by first and second valve connection lines 155, 160.Thus, the overflow chambers 145, 150 are fluidly connected to thesolenoid valve 105 and to the reservoirs 60, 65 via the draw tubes 130,140. The solenoid valve preferably comprises a single motive member 165contained within a solenoid housing 170. The motive member 165 providesat least two (2), two-way valves for connection between at least fourports 175, 180, 185, and 190. Preferably, the motive member has firstand second channels 195 and 197. The first channel 195 connects thefirst valve connection line 155 from the first aspirate reservoir 60 tothe vacuum source 107 through a vacuum line 200 or to an ambientpressure volume through a vent hose 205. The second channel of themotive member 165 connects the second valve connection line 160 to theambient pressure volume through the vent line 205 or to the vacuumsource 107 through the vacuum line 200. In one configuration of thesolenoid valve, the motive member 165 is a rotary member that rotatesunder the influence of a solenoid through a range of approximatelyninety degrees to exclusively connect either the first aspiratereservoir 60 or the second aspirate reservoir 65 to the vacuum source107 as shown in FIG. 2. Alternatively stated, the first channel eitherconnects the first reservoir 60 to the vacuum line 200 or to the ventline 205. Likewise, the second channel 197 of the motive member 165either connects the second aspirate reservoir 65 to the vent line 205 orto the vacuum line. Only one of the reservoirs 60, 65 is connected tothe vacuum source 107 at a time. The other reservoir is connected toambient air through the vent line 205. By way of example and not by wayof limitation, this is efficiently achieved by a single motive memberthat rotates or moves linearly between only two operating positions.

The connections to the vacuum source 107 and vent 205 are alternatedback and forth so that one of the aspirate reservoirs 60, 65 isconnected to the vacuum source 107 and the other is connected to thevent at all times. Preferably, this is achieved by a switch connected tothe solenoid valve 105, and wherein the solenoid valve is in a firstposition when the switch is closed and in a second position when theswitch is opened. That is, applying power to the solenoid valve placesit in a first position and removing power from the solenoid valve placesit in a second position indicated by the dashed arrows in FIG. 2.Preferably, the switch is provided by a timer switch 210 in a circuitconnected to a power source 215 as shown in FIG. 3. The timer switch 210can be adjusted to actuate its switch at a predetermined intervalcorresponding to a half cycle. Thus, the switch 210 will be turned on oroff after each half cycle and the motive member 165 will be moved to itsfirst or second position.

The solenoid could be replaced by a different solenoid valve. Forexample, the solenoid valve may comprise a piston member and more thanfour ports. The solenoid valve can connect the aspirate reservoirs torespective sources of vacuum and/or to respective vent lines. Furtheralternatively, the device could be manually operated. That is, insteadof employing a timer switch, a switch could be operated by hand. Furtheralternatively, manually operated valves could be provided so that aperson would be required to switch the connections to the reservoirsback and forth between vacuum and vent.

As indicated above, the amount of aspirate received into the reservoirs60, 65 optimally is equal to or slightly less than the amount refedduring a half cycle of the device. However, the amount refed variesduring feeding and over the course of recuperation. Therefore, therewill be periods of time during some half cycles when the aspiration isbeing applied, but little or no aspirate is flowing. Likewise there willbe periods when the aspirate being refed is completely withdrawn from areservoir before a current half cycle has ended. Since a reservoir isconnected to ambient during feeding from that reservoir, there is apotential for drawing air from the ambient into the feeding channel andeventually into the gastrointestinal tract. To prevent this fromhappening, a check valve is provided in each reservoir 60, 65 by a ball220. As shown, the ball 220 is buoyant and is thus positioned by theaspirate at a first level 225. When the aspirate reaches a maximumlevel, the ball floats at the maximum aspirate level as indicated at230. However, when the aspirate completely leaves the reservoirs 60, 65,the ball 220 seats in a sealed position as shown at 235. With aspiraterefeed being induced by gravity, this type of check valve will normallybe sufficient to prevent air from being drawn into the feeding channel35. On the other hand, if a positive pressure pump is employed to drawand refeed the aspirate, a more positive shutoff valve may be necessary.

As can be appreciated, the device 10 includes solenoid valve and timerdevice 240 as shown in FIG. 3. Furthermore, the solenoid valve and timerdevice 240 has special characteristics that are particularly beneficialwhen used with the overall device 10 described above. Specifically, thesolenoid valve 105 could be made automatic by an electrical circuitincluding a timer switch 210. The timer switch can comprisemicrocircuitry that includes a timer. The timer switch 210 can furtherinclude low voltage switch actuation that opens and closes the circuitconnected to the power source 215. Alternatively, the timer switch canbe made up of discrete electrical components that accomplish the samealternating timing function. Further alternatively, the timer switch caninclude a combination of electrical and mechanical elements that achievethe same alternating timing function.

FIG. 4 is a diagrammatic view of a device 245 according to a secondembodiment of the invention. This device 245 differs from the device 10described above in that the previously described device had two aspiratereservoirs whereas the device 245 has only one aspirate reservoir 250.The aspirate reservoir 250 in this case has a capacity equal to amaximum volume of aspirate to be retained in the reservoir. Any excessaspirate will spill into an overflow chamber 255. A further differenceis that the line connected to the reservoir 250 for refeeding aspiratedoes not also function to conduct aspirate to the reservoir 250. Thatis, the aspirate channel 30 is connected to the reservoir by anaspirating line 260 and the feeding channel 35 is connected to thereservoir 250 by an aspirate refeeding line 265. As such, aspiration andrefeeding can occur simultaneously from the same reservoir 245. However,aspiration cannot be effectuated by a vacuum source in fluidcommunication with the aspiration channel via the reservoir 245. If so,refeeding in the refeeding line 265 would be impeded. Therefore, apositive pressure pump 270 is provided in the aspirating line to drawaspirate toward the reservoir 245. Aspirate can be refed by agravitational force. However, a pressure source such as a pump could besubstituted. To assure flow in the right direction, a one way valve 275is also placed in the aspirating line 260. As in the previous embodimenta filter 280 is also preferably placed in the aspirating line 260, orbetween the aspirating line 260 and the aspiration channel 30. A checkvalve including a ball 220 like that described in the embodiment aboveis provided in the reservoir 250 of the device 245. This check valvefunctions substantially the same as that described above. Typically, thereservoir is open to the ambient air so that aspirate can be refed bygravity. Like the previous embodiment, the device is intended to be usedin addition to a supply of an unused feeding material that can be fedfrom a feeding bag 285 by a pump or gravity.

The device 245 of FIG. 4 is similar to the previously describedembodiment in that it advantageously provides for continuous or constantaspiration and refeeding of aspirate. While the device 245 requires apositive pressure source 270, device 245 does not require the solenoidand timer device 240 of the previously described embodiment of FIGS.1–3.

FIG. 5 shows a particular feeding tube assembly 305 that can be usedwith the device 10 of FIGS. 1 and 2 or with the device 245 of FIG. 4.The feeding tube assembly 305 can also be used with other feeding andaspirating devices. For example, the feeding tube assembly 305 can beused together with the single burette system of my U.S. Pat. No.6,447,472 issued Sep. 10, 2002, which is incorporated herein byreference. The feeding tube assembly 305 has a combination feeding andaspirating tube 310 that is connected to the feeding and aspiratingdevice 10 by a separate aspirating line 315 and a separate feeding line320. The feeding tube assembly 310 includes a branched section 325 thatincludes at least a first branch 327 and a second branch 329. As shownin FIG. 5, the first branch 327 can be selected for connection with theseparate aspirating line 315, and the second branch 329 can be selectedfor connection with the separate feeding line 320.

FIG. 6 shows the feeding tube assembly 305 in greater detail. A firstouter tube 330 is connected to the branched section 325, which in thiscase is in the form of a “Y”. The first outer tube 330 is connected tothe branched section by a sealed joint 332. A second inner tube 335 isselectively inserted into the outer tube 330 via the branched section325. Respective lengths of the inner tube 335 and the outer tube 330 areselected to provide a distally protruding portion 337 of the inner tube335 when the inner tube is inserted completely through the outer tube330 as shown in FIG. 5. This relationship provides for a distallylocated position of the feeding portion of the feeding and aspiratingtube 310 relative to the aspirating portion as will be described ingreater detail below.

It is to be understood that when the inner tube 335 is inserted to itsassembled state within the outer tube 330, an adapter 339 on the innertube 335 is received in the second branch 329 in a hermitically sealedrelation. Thus, no aspirate or feeding material can move in or out ofthe second branch 329 except through the inner tube 335. For thispurpose, the adapter 339 has an input opening 342 on a proximal endthereof for receiving and passing a feeding material into the inner tube335. A cap 345 connected to the adapter 339 by a flexible connector 347can be used to close the input opening 342 when the inner feeding tube335 is not in use. The inner tube 335 has a rounded distal end 350 toaid in passing the inner tube 335 through the outer tube 330 and toreduce the chance of injury to an intestinal tract of a patient. Theinner tube 335 has feeding openings 352 slightly proximately locatedrelative to the rounded distal end 350 and spaced along the inner tube335 in an alternating pattern as shown in FIG. 6.

The outer tube 330 has a distal portion 356 including a distal tip 359that has an aspirating opening 362 therethrough. Additional aspiratingopenings 365 are spaced along the outer tube 330 in an alternatingrelation as shown in FIG. 6. FIG. 7 is a sectional view of a portion ofthe feeding tube 310 shown as in an encircled region shown at 7 in FIG.5. This figure shows how the feeding openings 352 can be spaced alongthe inner tube 335. Likewise, the aspirating openings 365 can be spacedalong the outer tube 330. As described with regard to the embodimentsabove the feeding openings need to be located distally relative to theaspirating openings 365. This provides the advantage of feeding at alocation downstream in the gastrointestinal tract from a location atwhich excess gastrointestinal fluids and feeding material are aspirated.Thus, the feeding material and any medication in the inner tube 335 isless likely to be withdrawn during aspiration. This is especially sowhen the feeding tube is placed in the jejunum as described above.

In this particular embodiment of the feeding and aspirating tubecombination 310, the feeding openings 352 are located at distalpositions within a particular range of distances from the most distalaspirating opening 362 of the aspirating outer tube 330. As shown inFIG. 7, a distal most feeding opening 352 is located in a range fromapproximately 2 cm to approximately 3 cm from the distal opening 362 ofthe outer aspiration tube 330. The feeding opening 352 that is mostproximal is located in a range from approximately ½ cm to approximately2 cm from the distal opening 362 of the outer tube 330.

The relative sizes of the inner tube 335 and the outer tube 330 areimportant in determining the resistence to flow between the inner tube335 and the outer tube 330. For example, if the inner tube 335 is toolarge, then the flow of aspirate between the inner tube 335 and theouter tube 330 will be adversely restricted. Thus an outer diameter 370of the outer aspirating tube 330 should have a dimension in a range fromapproximately 10 French–18 French. In more common units, the outsidediameter 370 of the outer aspirating tube 330 can be in a range fromapproximately 3 mm to approximately 6 mm. The outer diameter 375 of theinner tube 335 can be in a range from approximately 4 French toapproximately 8 French. Likewise, in more common units the outerdiameter 375 of the inner tube 335 can be in a range from approximately1 mm to approximately 3 mm. In one particular configuration, the outerdiameter 375 of the inner tube 335 is approximately 6.5 French and theouter diameter 370 of the outer tube 330 is approximately 14 French.

While the inner tube 335 and the outer tube 330 are in their assembledstate the relationship between the inner tube 335 and the outer tube 330can be considered generally coaxial. This is the case even when theouter tube 330 fits loosely around the inner tube 335 to permitaspiration through the outer tube 330 while the inner tube 335 isdisposed inside the outer tube 330. Advantageously, the inner tube isremovable from the outer tube. Thus, the inner tube 335 and the outertube 330 form the assembly 305 that can be joined together as acombination feeding and aspirating tube 310 by an end user such as asurgeon or an assistant in a hospital or other facility. As such, amethod of feeding and aspirating with a feeding tube of the presentinvention includes the step of inserting an inner tube 335 through anouter tube 330. The method further includes sealing an external end ofthe inner tube relative to an external end of the outer tube. The methodalso includes placing the combination inner and outer tubes in thejejunum of the patient. This placement of the combination feeding andaspirating tube can be performed in any of the various manners set forthabove. However, it is to be understood that a small amount of feedingmaterial can be fed during insertion in order to prevent clogging of theinner tube by clotted blood or large particles from the gastrointestinal tract. The method can also include aspirating through theouter tube.

In another aspect of the invention, the method includes feeding for afirst predetermined period of time after an operation. After the firstpredetermined period of time has lapsed, the inner tube is removed.Feeding can subsequently be provided through the outer tube or throughanother separate feeding tube that is larger than the inner tube. Thefirst predetermined period of time can correspond to a period of time inwhich the patient recovers sufficiently for the gastrointestinal tractto be capable of accepting larger quantities of feeding material, andperhaps a courser feeding material. After the operation and before thefirst predetermined period of time has lapsed, feeding must be monitoredclosely in order to avoid overfeeding. Once the gastrointestinal tractfunction is capable of consistently absorbing the feedings, then themonitoring can be lessened or stopped. Once the feedings are beingreadily absorbed and monitoring has been stopped, the more costlytwo-reservoir system is no longer needed. Also, as the gastrointestinaltract becomes more capable of handling courser feedings, the expensivepredigested feedings are no longer required. Therefore, less expensivefeeding material can be fed and constant monitoring is no longerrequired.

It is to be understood that the term “positive pressure source”generally refers to a pump or an equivalent, such as a syringe orpressurized receptacle. The term “positive” refers to an “active” asopposed to a passive pressure means, such as a gravitational pressuremeans. It is also to be understood that vacuum source refers to anynumber of equivalents such as a pump, an aspirating syringe, or anegative pressure receptacle. One common vacuum source is that typicallyprovided by a hospital or other facility and piped throughout thefacility to the various stations including patients' rooms.

The embodiments and examples set forth herein were presented in order tobest explain the present invention and its practical application and tothereby enable those of ordinary skill in the art to make and use theinvention. However, those of ordinary skill in the art will recognizethat the foregoing description and examples have been presented for thepurposes of illustration and example only. The description as set forthis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the teachings above without departing from the spirit andscope of the forthcoming claims.

1. A method of feeding and aspirating comprising: inserting an innertube through an outer tube; sealing an external end of the inner tuberelative an external end of the outer tube; placing the combinationinner tube and outer tube in the jejunum of a patient so that each of aninternal end of the inner tube and an internal end of the outer tube arepositioned in the jejunum; feeding from externally of the patientthrough the inner tube to the jejunum of the patient; and aspiratingfrom the jejunum through the outer tube.
 2. The method of feeding andaspirating of claim 1, wherein: the step of feeding comprises feedingfor a first predetermined period of time after an operation; the methodof feeding and aspirating further comprises: removing the inner tubefrom the outer tube after the first predetermined period of time; andfeeding through one of the outer tube and another separate feeding tube.3. The method of feeding and aspirating of claim 1 wherein: the step offeeding further comprises feeding for a first predetermined period oftime after an operation; the method of feeding and aspirating furthercomprises: removing the inner tube from the outer tube after the firstpredetermined period of time; and at least one of feeding and aspiratingthrough the outer tube after the first predetermined period of time.